Monthly Archives: April 2014

Spectrum Wars – A Dynamic Spectrum Access Game Using Iris

One of the more interesting demo systems we’ve built recently using Iris has been a 4-player game called Spectrum Wars. The game shows how flexible software radios can dynamically change the properties of their wireless signals to avoid interference and efficiently use available spectrum. It also emphasizes the challenges of coordinating a transmitter and receiver to maintain a wireless link in a very dynamic spectrum environment.

Teams of two play the game – one team player controls a radio transmitter and the other controls a receiver. Graphical interfaces are used to manually choose the carrier frequency, bandwidth and gain. The objective of the game is to create a wireless link between the transmitter and receiver and to transfer as much data as possible over that link. At the same time, the opposing team tries to do likewise using the same spectrum band. A team can choose to play nicely by avoiding the signals of the opposing team, or to play aggressively by interfering with the signals of the opposing team and preventing them from creating and maintaining a link.

To make things more difficult a “primary user” (with priority access to the spectrum) also uses the spectrum band and transmits a high-power, narrow-bandwidth signal which sweeps to new randomly-selected carrier frequencies every 5 seconds.

Spectrum Wars was inspired by the spectrum challenge organised by DARPA in the US in 2013. The game was initially demonstrated at the CTVR Telecommunications Showcase in Dublin, in September 2013 ( and has since been played at FOSDEM 2014 in Brussels ( and the Future Internet Assembly in Athens ( More recently, it was enhanced with the addition of an automated team and demonstrated at IEEE DySPAN 2014 ( where it won the award for best demonstration.

In my next post, I’ll describe the Iris radios used to build Spectrum Wars.